Our increasingly mobile and mechanized society uses a variety of different fuels (e.g., gasoline, diesel fuel, ethanol, etc.) as energy. Liquid fuels are generally stored in liquid reservoirs such as underground storage tanks, above ground tanks, or any of a variety of different containers. Typically, liquid fuel reservoirs have inlets and outlets through which fuel can be added to and/or removed from the reservoir. These inlets and outlets may typically consist of a riser pipe extending from the reservoir. Internal to the riser pipe is a drop tube that typically includes an overfill valve adapted to respond once a predetermined level is reached in the liquid reservoir. To simplify manufacture and assembly, it is also known to provided the drop tube in a plurality of segments that are fastened together in series to form an overall drop tube assembly. As shown in U.S. Pat. No. 4,986,320, for example, the drop tube assembly includes an intermediate drop tube segment having opposed ends that are each correspondingly fastened to an upper and lower drop tube segment with fasteners extending through the respective walls of the segments.
Such configurations have proven to be very effective. To further enhance the beneficial nature of previous drop tube assemblies, there is a desire to provide a substantially fluid tight seal at the fastening location between the drop tube segments. A fluid tight seal may reduce or prevent fluid, such as vapor, from being released from the ullage area of the reservoir to the interior of the drop tube that might act as a chimney to vent the fluid to the surrounding atmosphere and potentially create an environmental concern.
To address potential concerns of vapor leakage, it is known to provide fastening sections with an epoxy layer to provide a fluid-tight seal at potential leak points. For example, it is known to provide a drop tube assembly, as shown in U.S. Pat. No. 4,986,320, with a conventional drop tube segment 500 described with respect to FIGS. 1–7 and 7A of the drawings herein. As shown in FIG. 4, the conventional drop tube segment 500 may include a fastening section 509 adapted to facilitate attachment between the drop tube segment 500 and another conventional drop tube segment that can be arranged as an upper drop tube segment 620. As shown in FIG. 7, the conventional drop tube segment 500 can be attached to the conventional upper drop tube segment 620 to form a conventional drop tube assembly 660. As described more fully below, the conventional fastening arrangement includes an epoxy layer, such as a layer of Loctite® epoxy-sealant for use as a cold weld bonding compound.
As shown in FIG. 1, the conventional drop tube segment 500 includes a conduit 502 with a first end portion 504 (see FIG. 3) and a second end portion 506. The first end portion 504 includes a wall 511 with an inner surface 511a and an outer surface 511b. Three fastener receiving structures 507a, 507b, 507c are radially disposed on the wall 511. In addition, each fastener receiving structure 507a, 507b, 507c comprises an opening that extends between the inner surface 511a and the outer surface 511b of the wall 511, along respective corresponding axes 508a, 508b, 508c, such that the openings comprise through openings that might permit fluid communication between the inner surface 511a and the outer surface 511b. 
The drop tube segment 500 further includes a valve assembly 510 with a valve member 512 pivotally associated with the first end portion 504 of the conduit 502. The valve assembly 510 further includes a float 530 and a linkage device 570 pivotally connected with the valve member 512 and in communication with the float 530 wherein the float 530 may facilitate in adjusting position of the valve member 512 with respect to the first end portion 504 in response to a liquid level in a liquid reservoir. As shown in FIGS. 1 and 3, the drop tube segment 500 is also known to include a conventional adjustable stop member 588 located below an O-ring sealing member 505 and adapted to engage the linkage device 570, as shown in FIG. 3, to limit a movement of the linkage device 570.
A conventional method of making a conventional drop tube assembly will now be described with respect to FIGS. 4–7 and 7A. As shown in FIG. 4, the previously-mentioned upper drop tube segment 620 is provided with an upper conduit 622 with a first end portion 624 and a second end portion 626. The upper conduit 622 includes a wall 628 with an inner surface 630 and an outer surface 631. An aperture 640 is formed in the wall 628 (e.g., by a drilling or a punching process) from the outer surface 631 to the inner surface 630. Due to the inwardly-directed forces present when forming the aperture 640, edges 642 of the aperture 640 may extend radially inwardly from the inner surface 630 of the wall 628 and/or burrs formed while making the aperture 640 may extend radially inwardly from the inner surface 630 of the wall 628.
As shown in FIG. 5, the second end portion 626 of the upper conduit 622 is inserted over the first end portion 504 of the conduit 502. As the aperture 640 passes over the sealing member 505, the outer edges 642 and/or burrs associated with the aperture 640 may damage the sealing member 505, for example, by gouging the sealing member 505 with the outer edges 642 and/or burrs associated with the aperture 640. Gouging of the sealing member 505 may form one or more grooves or other imperfections in the outer circumferential surface of the sealing member 505. In order to maintain a fluid tight connection with a seal including such surface imperfections, an epoxy layer 648 may be applied to the outer surface 511b of the wall 511 prior to insertion of the second end portion 626 of the upper conduit 622 over the first end portion 504 of the conduit 502.
As shown in FIG. 6, once the second end portion 626 of the upper conduit 622 is inserted over the first end portion 504 of the conduit 502, a stamping tool may be used to shape the aperture 640 adjacent the inner surface 630 of the wall 628 such that the edges 642 of the aperture 640 extend radially inwardly, or further radially inwardly, from the inner surface 630 of the wall 628. Shaping of the aperture also causes crimped portions 644 of the wall 628 adjacent the aperture 640 to at least partially enter the corresponding fastener receiving structure 507a, 507b, 507c. 
As shown in FIG. 7, after shaping the aperture 640, a fastener 646 may be inserted through the aperture 640 to engage the crimped portion 644 and a corresponding one of the fastener receiving structures 507a, 507b, 507c. The epoxy layer 648 may be effective to fill in any grooves and/or other imperfections in the outer circumferential surface of the sealing member 505 to provide a fluid tight seal between the drop tube segment 500 and the upper drop tube segment 620. Similarly, another epoxy layer 650 may be applied about the head of each fastener 646 associated with each fastener receiving structure 507a, 507b, 507c in order to provide a fluid tight seal at the fastener receiving structures 507a, 507b, 507c. Still further, as shown in FIG. 7A, a leak path may exist at the interface 588a between the adjustable stop member 588 and the wall 511. In order to provide a fluid tight seal, another epoxy layer 652 may be applied to a circumferential joint 629 between the upper conduit 622 and the conduit 502.
Application of an epoxy layer to provide fluid-tight sealing has proven very beneficial to reduce fluid vapor leakage. However, the addition of an epoxy layer typically greatly lengthens the installation process and the epoxy layer must cure for an extended period of time before the drop tube assembly may be installed with respect to the liquid reservoir. Currently, there is a need for drop tube assemblies that comprise a plurality of sections that may be connected together for immediate installation with respect to the liquid reservoir while providing a fluid seal at the fastening location between the drop tube segments.